Coulomb's Law Remains Tricky to Test at Home
I want to use physical laws as fluently as I speak. Coulomb's law, which gives the force between two point charges, is hard to test at home. I built an aluminium foil electroscope from a jar, wire, and foil, but charge decay from humidity makes it messy and non-quantitative. I'm seeking a more robust way to create repeatable charges and measure the inverse square law accurately.
Charging an metal ball cleanly and with home materials is proving kind of tricky.
- nh23423fefe
> But it's not at all obvious to me why the exponent a is 1 in nature
i think we can rule out any exponent just by dimensional analysis if you allow powers of q, then K has ambiguous units. Same reason you cant exponentiate unitful quantities
More specifically I think we can rule out even exponents by anti-symmetry of charge. That is q^2n = (-q)^2n which know is ruled out by experiment.
- sobellian
For two different indivisible charges, this is a bit slippery but I think a=1 by definition. How do we measure charge, practically speaking? By how much force is measured between it and a reference charge. So we take a=1 as a convention. But no experiment can disprove a=2 for indivisible charges as we would simply obtain charge through new units. For assemblies of charges the forces must add linearly due to conservation of momentum, so there we know a=1.
- smallmancontrov
Cat + Packing Peanuts
https://commons.wikimedia.org/wiki/File:Cat_demonstrating_st...